1999 Chevy Monte Carlo vehicle overheating

my car will be fine for a little bit then the temp gauge will start rising it will get 3/4 of the way to hot then jump back down to 1/4 way to cold as it gets warmer when it jumps it goes to about half way it never just stays at the middle it is always moving bck and forth is that ok? Ad if not wat could be wrong with it? Should I have the cooling sytem pressure checked?